code: def test_default_configuration(self):
      transformation, original = _test_preprocessing(
          KernelPCA, dataset="digits", train_size_maximum=2000
      )
      self.assertEqual(transformation.shape[0], original.shape[0])
      self.assertFalse((transformation == 0).all())
  
file_path: auto-sklearn/test/test_pipeline/components/feature_preprocessing/test_kernel_pca.py
imports: import sklearn.metrics
  from sklearn.linear_model import RidgeClassifier
  from autosklearn.pipeline.components.feature_preprocessing.kernel_pca import KernelPCA
  from autosklearn.pipeline.util import PreprocessingTestCase, _test_preprocessing, get_dataset
  import unittest
label_desc: Use image node_id 1 for calling the KernelPCAComponentTest obj's underlying member method code with example usage: obj.test_default_configuration() without return types